Abstract
Disequilibrium pattern analysis, a general method for analyzing evolutionary events acting on pairs of tightly linked polymorphic loci, is applied to a large sample of Danish individuals typed for A and B loci of the HLA (human leukocyte antigen) system. Cases of selection on particular haplotypes are revealed from patterns of linkage disequilibrium among the HLA haplotypes. These patterns cannot be explained by either population admixture or random genetic drift. Six haplotypes out of the total array of 273 haplotypes have been identified which show in varying extents the patterns indicating selection.